A shaft seal device is provided around a rotor of a rotary machine, such as a gas turbine or a steam turbine, to reduce the leakage rate of working fluid flowing to the low-pressure side from the high-pressure side. For example, a shaft seal device disclosed in the following PTL 1 is known as an example of the shaft seal device.
FIG. 9 is a view showing the schematic structure of a shaft seal device 110 in the related art. The shaft seal device 110 includes a housing 109 that is supported by the inner peripheral surface of a stator, and a seal body 112 that is disposed in a circumferential direction in the housing 109.
The seal body 112 includes a plurality of thin-plate seal pieces 120 that are laminated with a minute gap therebetween so that the thickness direction (the direction of the plane of paper of FIG. 9) of each thin-plate seal piece is parallel to the circumferential direction of the rotor (rotating shaft 6). Each thin-plate seal piece 120 is obliquely disposed so that an inner end portion (tip) of each thin-plate seal piece 120 in the radial direction of the rotor is positioned on the front side of a radially outer end portion (rear end) thereof in the rotational direction of the rotor. Rear ends of the thin-plate seal pieces 120 are connected to each other through a soldering portion 24, and tips thereof become free ends.
The thin-plate seal piece 120 of the seal body 112 is a flat plate-like member that has a predetermined width in the direction of the axis of the rotor. The seal body 112 is formed in a T shape having a head 120d, and the housing 109 includes a T-shaped internal space 109a corresponding to the T shape.
In the shaft seal device 110 having this schematic structure, the tips of the thin-plate seal pieces 120 come into contact with the rotor when the rotor stops. Further, when the rotor rotates, the tips of the thin-plate seal pieces 120 float from the outer periphery of the rotor by a dynamic pressure effect that is caused by the rotation of the rotor. Accordingly, the tips of the thin-plate seal pieces 120 do not come into contact with the rotor. For this reason, the wear of the thin-plate seal pieces 120 is suppressed in the shaft seal device 110. Accordingly, the life of the seal is lengthened.